Stool



FIG. 1 is a front view of the stool according to the present design;

FIG. 2 is a rear view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a left side view thereof; and,

FIG. 6 is a right side view thereof.

The broken lines in the drawings depict portions of the stool that form no part of the claimed design. 

CLAIM The ornamental design for a stool, as shown and described. 